1. Field
This apparatus relates to a disk drive diagnosis apparatus in a RAID system.
2. Description of the Related Art
FIGS. 8 and 9 are diagrams illustrating a conventional technique.
In FIG. 8, each disk drive 16 is housed in a device enclosure 11, and exchanges data with external equipment via a RAID control unit 10. Conventionally, the RAID control unit 10 and the disk drive 16 are interconnected by means of a fiber channel arbitrated loop (FC-AL) 15. In disk drive diagnosis, before a disk drive 16 is connected to a loop of the FC-AL 15, testing is performed as to whether or not loop initialization completes between the disk drive 16 and a port bypass circuit (PBC) 12. If the test result is normal, the disk drive 16 is determined to be normal, and is connected to the loop. If loop initialization does not complete, the disk drive is determined to be faulty, and is disconnected from the loop. A constituent element for making such a loop, thereby checking the disk drive for normality, is the PBC 12. At the same time, the RAID control unit 10 collectively obtains the diagnosis results of the disk drive 16 from the PBC 12, thereby making it possible to recognize the presence of a faulty disk drive.
However, as shown in FIG. 9, in the case where the device enclosure 11 and the RAID control unit 10 are interconnected via a fabric switch 17, the disk drive 16 requires procedures for login responsive to the fabric switch 17 such as FLOGI (login for assigning an address required for the fabric switch 17 to perform routing) or PLOGI (login for assigning a directory name to each disk drive) in addition to connection procedures by the FC-AL 15. These logins are performed for a login server 20 and a directory server 19 that exist in a processor 18 of the fabric switch 17. Therefore, in disk drive diagnosis, in addition to conventional loop initialization diagnosis, it is necessary to perform diagnosis for whether or not login is normally performed and to detect a faulty disk drive. However, this login process is performed without intervening the RAID control unit 10. Thus, there has been only one method for the RAID control unit 10 to issue commands, respectively, to the disk drive 16 and make checks on one-by-one basis in order for the RAID control unit 10 to recognize the presence of a faulty disk drive, such as an incomplete login process (in order to perform login diagnosis). Assume that the RAID control unit 10 issues commands to the disk drive 16 and determines whether or not the disk drive 16 is normal. If a disk drive 16 fails in such a case, no response to the command is provided. Therefore, there is a possibility that the issued command remains in a buffer of a port of a fabric switch connected to the device enclosure, inclusive of the disk drive that has failed, disabling not only the disk drive that has failed but also the entire device enclosure.